1. Field of the Invention
The present invention relates generally to a device for securing and tensioning a dulled band saw blade for sharpening purposes and, more particularly, to a device providing a retractable tensioning means to accommodate band saw blades of varying sizes.
2. Description of the Related Art
U.S. Pat. No. 3,460,407 issued to U. Volliner on Aug. 12, 1969 relates to a device for sharpening a band saw, including a centrally arranged adjusting device for simultaneously adjusting the heights of all the guide means of the device.
U.S. Pat. No. 3,802,299 issued to V. Idel on Apr. 9, 1974 also discloses a device for sharpening a band saw, including a bed for mounting a grinding mechanism, as well as an in-feed mechanism for moving the band saw blade transversely to the grinding mechanism. In addition, a pitch feed mechanism moves the saw blade longitudinally, while a resilient fixture clamps the blade on the machine's side and back surfaces.
U.S. Pat. No. 3,929,040, also issued to Idel, on Dec. 30, 1975 discloses an improved feed mechanism for his band saw sharpening machine. Supporting elements are used in the machine and are arranged such that they are inclined in the direction of the blade movement through the machine.
U.S. Pat. No. 4,064,770, also issued to Idel, on Dec. 27, 1977 discloses further improvements to the band saw sharpening machine, relating to the quality and finish of the band saw teeth being machined.
Finally, U.S. Pat. No. 4,587,869 issued to G. Hamer on May 14, 1986 discloses a method and apparatus for reconditioning worn band saw blades, particularly those blades having alternating right and left set teeth.
While there exists a multitude of devices for automatically sharpening the circular blade of a band saw machine (as indicated by the above examples), it may be somewhat expensive and impractical for an ordinary homeowner to own or use such a machine. In many cases, a dulled band saw blade is sharpened manually by applying a file, rasp, or other similar tool directly to the teeth of the blade. However, in order to properly sharpen a blade by hand, the blade must be firmly held in place by means of a vise or other securing mechanism. One disadvantage of this method is the relatively long time it takes to sharpen the entire length of the blade, since the blade must be continuously rotated within the narrow width of the vise.
A need, therefore, exists for a device which allows manual sharpening of band saw blades to be accomplished with relative ease by minimizing the number of times the blade must be rotated.